Burner assembly having a burner enclosure for a combustion system

ABSTRACT

A burner assembly having a burner enclosure for a combustion system is provided. The enclosure includes a first enclosure portion configured to receive air and fuel, a second enclosure portion, a partition disposed between the first enclosure and the second enclosure, and a passage connecting the first enclosure portion to the second enclosure portion such that the air and fuel may flow from the first enclosure portion to the second enclosure portion.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a nonprovisional patent application, andclaims the priority benefit of U.S. Application Ser. No. 62/448,753,filed Jan. 20, 2017, the text and drawings of which are herebyincorporated by reference in its entirety.

TECHNICAL FIELD OF THE DISCLOSED EMBODIMENTS

The presently disclosed embodiments generally relate to combustionsystems and, more particularly, to burner enclosures for combustionsystems.

BACKGROUND OF THE DISCLOSED EMBODIMENTS

In combustion systems, such as burner assemblies for ultra low NOxapplications generally found in HVAC/R units, a mixture of fuel and airis ignited in an enclosure to form a stable flame attached to a burnersurface, such as a burner mesh. Generally, ignition may result in asudden increase in pressure within the enclosure. The sudden pressureincrease may decrease flame stability within the enclosure, includingcausing flame blow off or the alternating detachment and attachment ofthe flame to the burner surface. Such action may also generate excessivenoise and/or vibrations within the assembly. Further, as the air-fuelmixture is introduced into the enclosure, the mixture may not becomesufficiently mixed to maintain acceptable flame stability and NOxlevels.

Therefore, there exists a need in the art for a burner enclosure thatimproves combustion stability and reduces the likelihood of flame blowoff and/or noise generation. Further, there exists a need in the art fora burner enclosure that improves mixing of the air-fuel mixture.

SUMMARY OF THE DISCLOSED EMBODIMENTS

In accordance with an embodiment of the present disclosure, a burnerenclosure for a combustion system is provided. The burner enclosureincludes a first enclosure portion configured to receive air and fuel, asecond enclosure portion including an outlet, a partition disposedbetween the first enclosure portion and the second enclosure portion,and a passage connecting the first enclosure portion to the secondenclosure portion such that the air and fuel may flow from the firstenclosure portion to the second enclosure portion.

The burner enclosure may further include an ignition source disposedadjacent to the outlet. The first enclosure portion and the passage maybe configured to at least partially mix the air and fuel. The passagemay be sized to minimize ignition blow-off. The passage may be sized tominimize noise generation. The passage may be spaced from the partition.The passage may be formed at least partially by the partition.

In accordance with an embodiment of the present disclosure, a burnerassembly for a combustion system is provided. The burner assemblyincludes a heat exchanger cavity, a burner head disposed in the heatexchanger cavity, and a burner enclosure operably coupled to the heatexchanger cavity, the burner enclosure including a first enclosureportion configured to receive air and fuel, a second enclosure portionincluding an outlet, a partition disposed between the first enclosureand the second enclosure, and a passage connecting the first enclosureportion to the second enclosure portion such that the air and fuel mayflow from the first enclosure portion to the second enclosure portion.

The burner assembly may further include an ignition source disposedwithin the heat exchanger cavity and adjacent to the outlet. The firstenclosure portion and the passage may be configured to at leastpartially mix the air and fuel. The passage may be sized to minimizeignition blow-off. The passage may be sized to minimize noisegeneration. The passage may be spaced from the partition. The passagemay be formed at least partially by the partition.

BRIEF DESCRIPTION OF DRAWINGS

The embodiments and other features, advantages and disclosures containedherein, and the manner of attaining them, will become apparent and thepresent disclosure will be better understood by reference to thefollowing description of various exemplary embodiments of the presentdisclosure taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a burner assembly in accordance withan embodiment of the present disclosure; and

FIG. 2 is a cross-sectional view of a burner assembly in accordance withan embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of this disclosure is thereby intended.

Referring now to FIG. 1, a burner assembly 10 for a combustion system inaccordance with an embodiment of the present disclosure is illustrated.The burner assembly 10 may be incorporated in an HVAC/R system oranother system not illustrated. The burner assembly 10 includes a burnerenclosure 12 and a burner head 14 disposed in a heat exchanger cavity16. The enclosure 12 includes a first enclosure portion 18 configured toreceive air and fuel 20. In an embodiment, the fuel is a combustiblegas, such as natural gas or propane to name non-limiting examples. Thefirst enclosure portion 18 is sized, shaped, and/or generally configuredto at least partially mix or allowing mixing of the air and fuel 20. Theenclosure 12 further includes a second enclosure portion 22 configuredto receive the air and fuel 20 from the first enclosure portion 18 forignition. In an embodiment, an ignition source 24 is disposed within theheat exchanger cavity 16, such as an igniter assembly. As illustrated inFIG. 1, a burner mesh 50 is disposed in the heat exchanger cavity 16adjacent the second enclosure portion 22. The flame and ignition occursin the heat exchanger cavity 16 in one or more embodiments of thepresent disclosure. The ignition in the heat exchanger cavity 16 mayoccur in ultra low NOx burner assemblies in one or more embodiments.

The enclosure 12 further includes a partition 26 disposed between thefirst enclosure portion 18 and the second enclosure portion 22. Thepartition 26 is configured to introduce an impedance over a HelmholtzResonance generated inside the burner assembly 10. The resonance is themain source of undesired tonal noise of the burner assembly 10. Thepartition 26 reduces and/or eliminates this tonal noise. In other words,the partition 26 is a shield against excessive noise and vibrationgenerated upon ignition of the air-fuel mixture 38 and/or during otheroperations of the burner assembly 10. The partition 26 includes a firstsurface 28 facing the first enclosure portion 18 and a second surface 30facing the second enclosure portion 22 in the embodiment illustrated inFIG. 1. In additional embodiments not shown, the partition 26 includesmore than two surfaces separating the first enclosure portion 18 fromthe second enclosure portion 22 or is formed from any structure thatacts to at least partially separate the first enclosure portion 18 fromthe second enclosure portion 22.

The enclosure 12 further includes a passage 32 connecting the firstenclosure portion 18 to the second enclosure portion 22. The passage 32is positioned, sized, shaped, and/or generally configured to at leastpartially mix the air and fuel 20. As illustrated in FIG. 1, the passage32 of one embodiment has a cross-sectional area 34, substantiallyperpendicular to a general direction of flow of the air and fuel 20 asillustrated in FIG. 1. The cross-sectional area 34 is also generallyless than a cross-sectional area 36 of the partition 26. The passage 32requires the flow of air and fuel 20 to converge and pass alongturbulence-inducing surfaces and edges to enhance mixing of the air andfuel 20 and form the air-fuel mixture 38, thereby improving combustionstability and decreasing NOx formation in the heat exchanger cavity 16.The combined air and fuel 20 may be less homogenously mixed than theair-fuel mixture 38 in accordance with embodiments of the presentdisclosure. The air and fuel 20 and the air-fuel mixture 38 is drawn orinduced through the passage 32 and other areas of the enclosure 12 by aninducer motor (not shown).

Generally, upon ignition of the air-fuel mixture 38, a significant andsudden increase in pressure may occur in the second enclosure portion 22to induce the flame to travel downstream and detach from the burner mesh50. With no passage 32, or an excessively small passage 32, there willlikely be a flame blow-off condition, which generates an undesiredrumbling noise in the burner assembly 10. Therefore, the passage 32 issized at or above a threshold dimension to minimize ignition or flameblow-off in an embodiment. In other words, the passage 32 is positioned,sized, shaped, and/or generally configured to act as a safety valve atthe time of ignition to maintain combustion stability.

However, if the passage 32 is too large, the enclosure 12 and/or thepartition 26 will not properly shield against excessive noise andvibration generated upon ignition of the air-fuel mixture 38 or duringother operations of the burner assembly 10. As such, the passage 32 issized at or below a threshold dimension to dampen or minimizetransmission of noise and/or vibrations generated by ignition or otheroperations. One of ordinary skill in the art will recognize that thesize, shape, and/or configuration of the passage 32, the partition 26,and/or the first and second enclosure portions 18, 22 will significantlyaffect the threshold dimension for the passage 32.

In particular embodiments, the passage 32 has a cross sectional areafalling within a range between about 0.70 square inches and about 7.00square inches. The passage 32 has a cross sectional area falling withina range between about 0.20 square inches and about 20.00 square inchesin further embodiments. The ratio of the cross sectional area of thepassage 32 relative to an area of the partition 26 falls within a rangeof between about 0.02 and about 0.35 in particular embodiments. Theratio of the cross sectional area of the passage 32 relative to the areaof the partition 26 falls within a range of between about 0.01 and about1.00 in further embodiments. The ratio of the cross sectional area ofthe passage 32 relative to the area of the partition 26 is less thanabout 0.01 in an embodiment and greater than about 1.00 in anembodiment.

The passage 32 of the embodiment illustrated in FIG. 1 is essentiallyshown as a conduit spaced from the first enclosure portion 18 and thesecond enclosure portion 22. In other words, the passage 32 of FIG. 1has separate walls 40 not shared by the first enclosure portion 18, thesecond enclosure portion 22, or the partition 26.

Referring now to FIG. 2, the burner enclosure 12, in accordance with afurther embodiment of the present disclosure, is illustrated. Asillustrated in FIG. 2, the passage 32 of one embodiment is formed atleast partially by the partition 26. As such, a shared wall 42 formspart of the first enclosure portion 18 and the passage 32. Further, anouter wall 44 of the enclosure 12 forms part of the passage 32. Onehaving ordinary skill in the art will recognize the variousconfigurations that may be formed from the first and second enclosureportions 18, 22, the partition 26, and the passage 32 to form thepassage 32, and such configurations form part of the present disclosure.

One will appreciate that the embodiments described in the presentdisclosure provide the burner assembly 10 having the burner enclosure 12that improve operation of a combustion system. The passage 32 ispositioned, sized, shaped, and or configured to enhance mixing of theair and fuel 20 as the mixture flows between the first enclosure portion18 and the second enclosure portion 22. Such mixture enhancementimproves combustion stability and reduces NOx levels. Further, thepassage 32 and partition 26 of the burner enclosure 12 reduce thelikelihood of flame blow-off during the rapid pressure increase ofignition. Finally, the passage 32 and partition 26 reduce thetransmission of noise and/or vibration originating from the secondenclosure portion 22. The structures and functions described hereinimprove the efficiency and reliability of a combustion system andimprove the comfort of the user of such a system.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly certain embodiments have been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. A burner enclosure for a combustion system, theenclosure comprising: a first enclosure portion configured to receiveair and fuel; a second enclosure portion including an outlet; apartition disposed between the first enclosure portion and the secondenclosure portion; and a passage connecting the first enclosure portionto the second enclosure portion such that the air and fuel may flow fromthe first enclosure portion to the second enclosure portion.
 2. Theenclosure of claim 1, further comprising: an ignition source disposedadjacent to the outlet.
 3. The enclosure of claim 1, wherein the firstenclosure portion and the passage are configured to at least partiallymix the air and fuel.
 4. The enclosure of claim 1, wherein the passageis sized to minimize ignition blow-off.
 5. The enclosure of claim 1,wherein the passage is sized to minimize noise generation.
 6. Theenclosure of claim 1, wherein the passage is spaced from the partition.7. The enclosure of claim 1, wherein the passage is formed at leastpartially by the partition.
 8. A burner assembly for a combustionsystem, the assembly comprising: a heat exchanger cavity; a burner headdisposed in the heat exchanger cavity; and a burner enclosure operablycoupled to the heat exchanger cavity, the burner enclosure comprising afirst enclosure portion configured to receive air and fuel; a secondenclosure portion including an outlet; a partition disposed between thefirst enclosure and the second enclosure; and a passage connecting thefirst enclosure portion to the second enclosure portion such that theair and fuel may flow from the first enclosure portion to the secondenclosure portion.
 9. The assembly of claim 8, further comprising anignition source disposed within the heat exchanger cavity and adjacentto the outlet.
 10. The assembly of claim 8, wherein the first enclosureportion and the passage are configured to at least partially mix the airand fuel.
 11. The assembly of claim 8, wherein the passage is sized tominimize ignition blow-off.
 12. The assembly of claim 8, wherein thepassage is sized to minimize noise generation.
 13. The assembly of claim8, wherein the passage is spaced from the partition.
 14. The assembly ofclaim 8, wherein the passage is formed at least partially by thepartition.